Dimension reduction is the major consideration for design an optical imaging lens in recent years. When reducing the length of the optical imaging lens, however, achieving good optical characteristics becomes a challenging problem.
U.S. Pat. Nos. 7,480,105, 7,639,432, 7,486,449 and 7,684,127 all disclosed an optical imaging lens constructed with an optical imaging lens having five lens elements. The transition of refracting powers of the first two lens elements in U.S. Pat. Nos. 7,480,105 and 7,639,432 is negative-positive, and those in U.S. Pat. Nos. 7,486,449 and 7,684,127 are both negative-negative. However, such configurations still fail to achieve good optical characteristics, and further, fail to reduce the size of the whole system, because the lengths of the optical imaging lenses thereof fall into the range of 10˜18 mm.
U.S. Patent Publication No. 2011/0013069, and 2011/0249346, and U.S. Pat. No. 8,000,030 all disclosed an optical imaging lens constructed with an optical imaging lens having five lens elements. The transition of refracting powers of the first two lens elements in these three documents is the better positive-negative. However, the configurations of the surface shapes from the third to fifth lens elements thereof are unfavorable for improving the optical aberrations and meanwhile shortening the length of the optical imaging lens, therefore, for achieving better imaging quality, the lengths of the imaging lens are unable to be shortened. For example, the lengths of some imaging lens reach 6.0 mm, and this needs for improvement.
Therefore, there is needed to develop optical imaging lens with a shorter length, while also having good optical characters.